Air refrigerating apparatus



April 28, 1925. v 1,535,848

A. H. NICHOLSON AIR REFRIGERATING APPARATUS Patented Apr. 28,, 1925.

umrao Y STATES ARTHUR morn NICHOLSON, or'woacEsrna, ENGLAND.

AIR REFRIGERATING APPARATUS.

Application filed September To all whom it may concern:

Be it known that I, ARTHUR HAROLD NIoHoLsoN, a subject of His Majesty the Kin of Great Britain, residing in Worcester, ngland, have invented certain new and useful Improvements in Air Refrigerating Apparatus, of which the following is a specification.

The invention relates to compressed-air cold-producing apparatus for cooling-chambers and refrigerators and is more particularly applicable to conditions in which the bulk of the materialsto be cooled is comparatively small, such as in the-ordinary domestic requirements now frequently met by the ice box or refrigerator.

The invention is of the known type in which a pistonis caused to reciprocate in a cylinder and to force air or other gas under pressure into a number of small tubes connected to the cylinder head and closed at the end furthest from the head. The tubes are disposed in a chamber and the air or.

other gas is cooled by the circulation in this chamber of'a current of air or water and at the succeeding stroke of the piston the expanded and still further cooled air escapes from the cylinder and flows through a jacket surrounding the refrigerating chamher or through pipes coiled in the said chamber.

The invention consists of an improved apparatus of this type which is of very simple construction and eflicient in action.

The pump Works on a two-stroke cycle and the piston on its outward stroke compresses the air in the crank case and at the end of this stroke uncovers ports at or about this end of the cylinder.

One of the ports leads to a pipe connected with the jacketof, or tubes co1led in, the refrigerating chamber, the air compressed in the crank case passes through the other port and scavenges the air, expanded during the o expansion stroke of the piston,.through the .port connected to the jacket of the refrigerating chamber. 7

The ports are closedat the commencement of the return stroke of the piston and the air is v compressed in. the cylinder head,

while fresh air is admitted through an inlet valve in the crank case, or through a port in the cylinder wall uncovered when the piston is at the end of its inward stroke. The

%: inlet valve or port is, preferably, connected 3', 1924. Serial No. 735,666.

to the exit from the air erating chamber.

If the air inlet in the crank case is connected' to the jacket of the refrigerating chamber the working medium flows in a closed circuit and gases other than air can be used for this purpose.

The inner end of the piston is preferably arched or domed so as to deflect the incoming air towards the head of the cylinder and the head is formed with a recess conforming to the "domed end of the piston, allowing only the necessary working clearance at the end of the stroke.

'Although it has been assumed that only one-cylinder is provided it is obvious that the invention is not restricted to the use of a single cylinder.

The refrigerating chamber may be in the form of a cupboard for keeping food or a receptacle for freezing water. v

If air circulation is used for cooling the compressed air in the chamber connected to the cylinder head, the circulation may be in duced by natural draft or by a fan.

Figs. 1 and 2 of the accompanying drawings show diagrammatically in vertical section examples of a cold-producing apparatus according to the invention.'

In igQ 3 the jacket surrounding the refrigerating chamber is replaced by coiled tubes.

Referring to Fig. 1, l is the cylinder, 2 the piston, 3 a crank driven manually or by any suitable motor, 4 the connecting rod connected to the gudgeon pin 5 in the usual manner. In the chamber 6 secured to the head of the cylinder are disposed tubes 7, open to the cylinder 1 at their lower ends jacket of the refrig- "and closed at their *upper ends, in. which tubes air is compressed on the upward stroke of the piston.

The piston is dome-shaped and the head 1 t cylinder is provided with a correspondin ly formed recess'8. Cooling water. is caused to circulate in the chamber 6- round the tubes 7, in the example illustrated,

entering by a pipe 9 and leaving by a pipe 10. I

The crank 3 rotates in the crank case 11 and the lower part 12 of the wall-of the cylinder 1 is formed thicker on one side than the remaining portion of said wall'and a passage 13 in said thickened portion is formed through which air compressed in the crank case can pass into the upper part of the cylinder.

Air is supplied to the crank case through an inlet 14 and a non-return valve 15, and cooled air passes through an outlet 16 in the cylinder 1 when this outlet is uncovered by the descent of the piston 2 to its lowest posi tion represented in Fig. 1.

A pipe 17 is connected to the outlet 16 and leads to the jacket 18 of the refrigerating chamber 19. The cold air leaves the jacket of the refrigerating chamber by the exit 20, which may be connected to the inlet 14 to the crank case, or, if air instead of water is used as the medium for cooling the tubes 7, may enter the chamber 6.

The action is as follows As the piston 2 descends it compresses the air in the crank case; the air under pressure passes through the passage 13 and scavenges the cooled and expanded air, present in the upper part of the cylinder, through the outlet 16 into the jacket 18 of the refrigerating chamber 19. The scavenging action is assisted by the dome-shaped formation of the piston which deflects the air flowing from the passage 13 towards the cylinder head.

At the commencement of the upstroke of the piston the passage 13 and the outlet 16 are closed and the air above the piston is compressed and driven into the tubes 7 Where it is cooled by the circulation of water or air in the chamber 6.

On the down-stroke of the piston the cooled air is expanded and further cooled.

The example shown in Fig. 2 diflers from that shown in Fig. 1 in that the inlet valve 15 of Fig. 1 is replaced by a port 21 through which air or other gas is drawn into the cylinder 1 when the piston 2 is at the end of its inward stroke. The inlet 21 is preferably connected to the outlet 20 of the jacket 18 of the refrigerating chamber 19. A fan 22 is shown for inducing a flow of air in the chamber 6.

In Fig. 3 the jacket surroundin the refrigerating chamber 19 is replaced y coiled tubes.

Having thus described the nature of my said invention .and the best means I know of carrying the same into practical effect, I claim 1. A refrigerating apparatus comprising,

in combination, a pump cylinder having an outlet in its wall, a piston reciprocating in said cylinder, a crank case connected to one end of said cylinder, a crank rotatable in said crank case, a connecting rod connecting said piston and said crank, a chamber connected to the other end of said cylinder, tubes in said chamber, closed at one end and open at the other end to said cylinder, means for cooling said tubes, means for admitting gaseous fluid to said crank case, a refrigerating chamber and a pipe connecting the outlet of said cylinder With said refrigerating chamber.

2. A refrigerating apparatus comprising, in combination, a pump cylinder having an outlet in its Wall, a piston reciprocating in said cylinder, a crank case connected to one end of said cylinder, a crank rotatable in said crank case, a connecting rod connecting said piston and said crank, a chamber connected to the other end of said cylinder, tubes in said chamber closed at one end and open at the other end to said cylinder, means for cooling said tubes, means for admitting gaseous fluid to said crank case, a refrigerating chamber, a jacket around the refrigerating chamber, and a pipe connecting the outlet of said cylinder with said jacket, and a connection between said jacket and the means for admitting gaseous fluid to said crank case.

3. A refrigerating apparatus comprising, in combination, a pump cylinder having in its Wall an inlet port and an outlet port, a piston reciprocating in said cylinder and adapted to cover said inlet and outlet ports at the beginning of its stroke, a crank case connected to one end of said cylinder, a crank rotatable in said crank case, a connecting rod connecting said piston and said crank, a chamber connected to the other end of said cylinder, tubes in saidchamber closed at one end and open at the other end to said cylinder, means for cooling said tubes, means for admitting gaseous fluid to said crank case, a refrigerating chamber, a jacket around said refrigerating chamber, a pipe connecting the outlet of said cylinder with said jacket, and means connecting said crank case and the inlet port of said cylinder.

In testimony whereof I have signed my name to this specification.

ARTHUR HAROLD NICHOLSON. 

